Removed unused param from ContentResponse::build()

Removed the isHomePage param from one of the variants of
`ContentResponse::build()`. The other overload is dangerous since
failing to review&update all of its call site may result in changed
semantics. Will do it in a couple of separate commits.

src/server/internalServer.cpp

@@ -623,7 +623,7 @@ InternalServer::get_matching_if_none_match_etag(const RequestContext& r) const
 
 std::unique_ptr<Response> InternalServer::build_homepage(const RequestContext& request)
 {
-  return ContentResponse::build(*this, m_indexTemplateString, get_default_data(), "text/html; charset=utf-8", true);
+  return ContentResponse::build(*this, m_indexTemplateString, get_default_data(), "text/html; charset=utf-8");
 }
 
 /**

src/server/response.cpp

@@ -445,11 +445,10 @@ std::unique_ptr<ContentResponse> ContentResponse::build(
   const InternalServer& server,
   const std::string& template_str,
   kainjow::mustache::data data,
-  const std::string& mimetype,
+  const std::string& mimetype)
-  bool isHomePage)
 {
   auto content = render_template(template_str, data);
-  return ContentResponse::build(server, content, mimetype, isHomePage);
+  return ContentResponse::build(server, content, mimetype);
 }
 
 ItemResponse::ItemResponse(bool verbose, const zim::Item& item, const std::string& mimetype, const ByteRange& byterange) :

src/server/response.h

@@ -99,8 +99,7 @@ class ContentResponse : public Response {
       const InternalServer& server,
       const std::string& template_str,
       kainjow::mustache::data data,
-      const std::string& mimetype,
+      const std::string& mimetype);
-      bool isHomePage = false);
 
   private:
     MHD_Response* create_mhd_response(const RequestContext& request);